Contractors take great pride in their tools, and a fire extinguisher is an essential safety tool for every wood flooring job. Having a good understanding of the various types of fire extinguishers, and how to properly operate them, will minimize risk to you, your crew, your
customer, your vehicles, and your job site.
Fires are classified according to the type of fuel that is burning. If you use the wrong type of extinguisher on the wrong class of fire, you might make matters worse. It is important to understand the different fire (or fuel) classifications. Following are the types of fires most common to wood flooring job sites:
- Class A – Ordinary combustibles such as wood, cloth, paper, rubber, and many plastics.
- Class B – Flammable liquids such as gasoline, oil, grease, tar, oil-based paint, lacquer, and flammable gas.
- Class C – Energized electrical equipment including wiring, fuse boxes, circuit breakers, machinery, and appliances.
Different types of fire extinguishers are designed to fight different classes of fires. The three most common types of fire extinguishers are:
- Water
These extinguishers are also called Air Pressurized Water or APW extinguishers. They are designed for Class A fires only. - Carbon Dioxide or CO2
These extinguishers are designed for Class B, and Class C fires only. - Dry Chemical
These extinguishers are also called ABC, BC, and DC extinguishers. They are designed for Class A, B, or C fires.
Dry Chemical extinguishers are the type of extinguisher required for the hardwood flooring industry. These extinguishers, which are often referred to as ABC extinguishers, are clearly labeled. They are designed to put out fires by coating the fuel with a thin layer of dust, thus separating the fuel from the oxygen in the air. The powder works to interrupt the chemical reaction of the fire. While installing or sanding and finishing hardwood floors, it is important you keep ABC-rated fire extinguishers nearby to handle potential fires that could happen on the job site.
Using a Fire Extinguisher
The following steps should be followed when responding to an incipient/beginning stage fire:
- Sound the fire alarm and call 911.
- Identify a safe evacuation path before approaching the fire. Do not allow the fire, heat, or smoke to come between you and your evacuation path.
- Select the appropriate type of fire extinguisher.
- Discharge the extinguisher within its effective range using the P.A.S.S. technique (Pull, Aim, Squeeze, Sweep).
- Pull the pin by twisting it (this will also break the tamper seal).
- Aim at the bottom of the fire with the extinguisher nozzle or hose and work upward.
- Squeeze the trigger to release the extinguishing agent.
- Sweep back and forth, holding flat and level until the fire
is extinguished.
- Back away from an extinguished fire in case it flames up again.
- Evacuate immediately if the extinguisher is empty and the fire is not out.
Before deciding to fight any fire, check to see if the fire is spreading rapidly. The time to use an extinguisher is at the beginning stages of the fire. If the fire is already spreading quickly, it is best to simply evacuate the building. Also, do not fight the fire if you don’t have the adequate or appropriate equipment, especially as it relates to extinguishers; there is the possibility that you might inhale toxic smoke. You also should not fight a fire if your instincts tell you not to.
Fire Prevention
There are many different ways Class A fires can be caused and prevented on the job site. Spark fires can be caused by the sparks created when sanding over exposed nails or other metal objects. Always check floors to make sure nails are not exposed before sanding floors or ensure proper procedures are implemented when sanding floors where nails cannot be set. Spark fires can also be caused by improperly aligned equipment.
Friction fires can be caused by dull sanding paper, overworked paper, or improper selection of paper for the particular job. To avoid friction fires, be sure to switch out your sanding paper regularly and make careful paper selections.
Spontaneous combustion can occur due to wood dust igniting in the dust-collection bag when a new floor is being sanded. The heat created from the friction of the machine and sandpaper on the floor can increase to the point that the dust begins to smolder inside the bag, vacuum, or container. Wood dust must reach a temperature of 400 °F (204 °C) for it to ignite. Combustion happens much more frequently, however, when a floor is being resanded. The old finishes that are on the floor become ground into a fine powder. Again, the heat created by friction can cause spontaneous ignition. Resanding a freshly finished floor can pose additional risks due to the solvent and wood dust combination.
Sanding dust should be disposed of safely. Keep an eye on the dust collection bags, vacuums, or containers on all equipment. Empty the bags often in a proper container. Also, empty dust collection bags before transporting the machine or leaving the job site – even if you are just leaving for a short time.
Always remove dust receptacles and dust collection systems from the job site at the end of every day and dispose of them in a proper manner.
The most common type of spontaneous combustion in the wood flooring industry is caused by stain rags that are not disposed of properly. Oil-based stains, natural oils, varnishes, shellacs, polyurethanes, and paint thinners are common products that can be culprits. Spontaneous combustion occurs when the solvent or substance begins to oxidize. This process causes an exothermic reaction, meaning it releases heat. If the heat has no way to escape, like in a pile of rags, the temperature will continue to rise to a level high enough to ignite the rags. A cotton rag containing any amount of stain residue has the perfect surface area-to-mass ratio to spontaneously combust. Therefore, you should dispose of rags in an airtight metal container.
Class B fires are caused by flammable liquids and their vapors. On a wood flooring job site, these can include things like lacquer thinner, mineral spirits, shellac, and conversion varnishes. You can minimize the risk of Class B fires by turning off pilot lights and all ignition sources before using flammable liquids on the job site.
Class C electrical fires are caused by faulty cords, loose connections, breaker box fires, bad switches, faulty equipment, or improper cord selection.
Final Thoughts
In closing, always remember to keep safety top of mind and remember that smoking should always be prohibited on the job site and in the truck.
Here are some additional final fire extinguisher considerations:
- Always have two extinguishers on hand, a minimum of one in the truck and one on the job site.
- Know how to operate them.
- Hold them flat and level.
- Check for and maintain expiration dates.
Paul Hoffeditz is the Battalion Chief with the Rock Island Fire Department in Rock Island, Illinois. He has been a firefighter for 23 years.